Ordered mesoporous hairbrush-like nanocarbon assembled microfibers for solid-phase microextraction of benzene series in oilfield sewage.

Abstract

The development of advanced functional nanomaterials for solid-phase microextraction (SPME) remains an imperative aspect of sample pretreatment. Herein, we introduce a novel SPME fiber consisting of graphene fibers modified with ordered mesoporous carbon nanotubes arrays (CNTAs) tailored for the determination of benzene series in oilfield wastewater, which is synthesized by an ionic liquid-assisted wet spinning process of graphene nanosheets, followed by a precisely controlled growth of metal-organic framework and subsequent pyrolysis treatment. The resulting robust microfiber structure resembles a "hairbrush" configuration, with a crumpled graphene fiber "stem" and high-order mesoporous CNTAs "hairs". This unique architecture significantly enhances the SPME capacity, as validated by gas chromatography-mass spectrometry. The hairbrush-like nanocarbon assembled microfibers possess structural characteristics, a high specific surface area, and numerous binding sites, offering efficient enrichment of benzene series compounds in oilfield wastewater, including benzene, ethylbenzene, m-xylene, p-xylene, and toluene. Our analysis demonstrates that these microfibers exhibit broad linear ranges (0.2-600μg L-1), low detection limits (0.005-0.03mg L-1), and excellent repeatability (3.2-5.5% for one fiber, 2.1-6.7% for fiber-to-fiber)for detection. When compared to commercial alternatives, these hairbrush-like nanocarbon-assembled microfibers exhibit significantly enhanced extraction efficiency for benzene series compounds.